Field of the Invention
The present invention relates to motor vehicle tyres. In particular, the present invention relates to tyres intended to be mounted on the rear wheel of “supersport” motor vehicles having large engine capacity (e.g. 600 cm3 or higher), and/or high power (e.g. 170-180 hp or higher), also used on tracks.
Description of the Related Art
In recent times a trend has been observed to introduce in the market motor vehicles for supersport use having increasingly high power. For example, motor vehicles for road use having an engine capacity of 1000 cm3 or higher, with powers of 180 hp, are in fact already available on the market.
For ensuring such high performances, the tyres mounted on the wheels of such motor vehicles shall have very good features as regards the grip to the ground, so as to be able to effectively transfer the high traction torque to the ground, both while running on a straight path and while accelerating on leaving a bend, as well as to ensure an effective braking action. The grip becomes a really critical issue above all when running on wet road surfaces.
For ensuring to the motorcyclist that such performances are reached in a fully safe condition, the tyres shall ensure, together with a very good grip to the ground, behaviour stability both while running on a straight path and while running on bends, particularly in conditions of high acceleration/deceleration. In fact, a stable behaviour of the tyre indicates its capacity to effectively dampen perturbations transmitted by the unevenness of the road surface while running, so that such perturbations are not propagated to the motor vehicle, thus compromising the driving stability.
EP906836 describes a tyre for a two-wheeled vehicle comprising a tread band having at least one groove extending axially from the tread centre to the tread edges. In a first axial region of the tread band, which is the central region of the tread band and is intended to contact the ground when moving in a straight line, the groove is arranged substantially circumferentially. In a second axial region at the axial edge of tread band, which is the region intended to contact the ground when the vehicle is cornering at the maximum camber angle, the alignment of the grooves is substantially transverse. In a third axial region, which is the region of the tread band between the first central region and the second region, and which is the region intended to contact the ground when the vehicle is cornering at a camber angle less than the maximum one, the alignment changes progressively axially outwardly from substantially circumferential to substantially transverse so that in the first, second and third axial regions of the tread band the grooves are substantially aligned with the resultant forces acting on the tread band surface in the contact region between the tread band and the ground.